Aldosterone is predominantly synthesized in the adrenal glands. In addition, local aldosterone synthesis has been found in the heart and vasculature and aldosterone synthesis in adipocytes is discussed. Aldosterone exerts its effects via the mineralocorticoid receptor (MR). Besides the well described MR in the distal tubule of the kidney MR have also been detected in other organs such as the vasculature and a paracrine mode of action is discussed. Recently it has been described, that MR can be activated independent of aldosterone in hypertensive and obese rats 1. Aldosterone promoted end organ damage is mainly found in the cardiovascular system and the kidney. Inflammation and activation of different factors promotes fibroblast growth and matrix production resulting in myocardial fibrosis, vascular remodelling and renal fibrosis. Aldosterone appears to be involved in all steps of this process by synthesis of reactive oxygen species, induction of inflammation and growth factors like TGF-Beta and connective tissue growth factor. Taken together aldosterone - as the MetSyn- is an independent cardiovascular risk factor 5.